1. Field of the Invention
The present invention relates to a digital TV, and more particularly to a video format converting apparatus which converts a format of an input video.
2. Description of the Related Art
With introduction of a digital TV and development of various display devices, they provide more various kinds of videos than an existing analog TV. To convert various sizes of input videos to different sizes of output videos, a format converter is essentially required.
FIG. 1 is a block diagram showing a related art video format converting apparatus. If a format conversion of an input video is required, a first format converter 11 is used for decreasing the size of the input video while a second format converter 13 is used for increasing the size of the input video. At this time, both the first format converter 11 and the second format converter 13 include horizontal and vertical format converters. A memory 12 is arranged between the first and second format converters 11 and 13, and stores the decreased input video or original input video and then outputs the stored input video to the second format converter 13.
In the aforementioned related art video format converting apparatus, the first format converter 11 is located at the front end of the memory 12 while the second format converter 13 is located at the rear end of the memory 12. In this case, the format conversion can effectively be performed with decreasing the capacity of the memory. However, to this end, two format converters are required. This could lead to increase of hardware.
Accordingly, the present invention is directed to a video format converting apparatus that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a video format converting apparatus which optionally converts the sizes of input and output videos.
Another object of the present invention is to provide a video format converting apparatus that decreases and increases the size of a video using one format converter, thereby minimizing the capacity of a memory and hardware.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a video format converting apparatus according to the present invention includes a mode generator for generating a control signal of required data flow and a clock required for format conversion by determining a format conversion structure after receiving format data of input and output videos, a format converter of which input/output data path is controlled to a corresponding operation mode by the control signal, for independently format converting the input video synchronized with the clock in vertical and horizontal directions, and a plurality of multiplexers for providing proper video to the format converter in accordance with the signal of the mode generator.
The mode generator outputs a display clock synchronized with the output video if increase of the input video is required, and outputs an input clock synchronized with the input video if decrease of the input video is required.
The format converter includes a vertical format converter for vertically increasing or decreasing the input video, a horizontal format converter for horizontally increasing or decreasing the input video, and a memory for storing either the input video or the video vertically or horizontally decreased in accordance with the operation mode determined by the mode generator and outputting the stored video to a display device without further processing or outputting the stored video to the display device after format converting it through the vertical format converter or the horizontal format converter.
If it is determined by the mode generator that increase of the input video is required in vertical and horizontal directions, the input video is stored in the memory under the control of the mode generator and input to the vertical format converter to increase the number of vertical lines. The video having the increased number of the vertical lines is input to the horizontal format converter to increase the number of horizontal pixels and then output to the display device.
If it is determined by the mode generator that decrease of the input video is required in vertical and horizontal directions, the input video is input to the horizontal format converter under the control of the mode generator to decrease the number of the horizontal pixels. The video having the decreased number of the horizontal pixels is input to the vertical format converter to decrease the number of the vertical lines, and the video decreased in vertical and horizontal directions is stored in the memory and then output to the display device.
If it is determined by the mode generator that decrease of the input video is required in vertical direction and increase of the input video is required in horizontal direction, the input video is input to the vertical format converter under the control of the mode generator to decrease the number of the vertical lines, and the video having the decreased number of the vertical lines is stored in the memory, is input to the horizontal format converter to increase the number of horizontal pixels, and is finally output to the display device.
If it is determined by the mode generator that increase of the input video is required in vertical direction and decrease of the input video is required in horizontal direction, the input video is input to the horizontal format converter under the control of the mode generator to decrease the number of the horizontal pixels, and the video having the decreased number of the horizontal pixels is stored in the memory, is input to the vertical format converter to increase the number of the vertical lines, and is finally output to the display device.
If it is determined by the mode generator that the size of the input video is equal to the size of the output video, the input video is stored in the memory under the control of the mode generator and then output to the display device.
In the preferred embodiment of the present invention, in format converting various sizes of the input videos to adapt to the various kinds of the display devices, a structure of the format converting apparatus is automatically varied in accordance with the sizes of the input and output videos, and a proper operational clock is selectively used to decrease the capacity of required hardware.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.